Essential oils are traditionally obtained from plants by steam distillation. This is an effective method but demands a high energy consumption and a long processing time. Solvent-Free Microwave Extraction (SFME) is a new microwave based distillation process [1] which uses no additional added water or solvent. Preliminary studies [2] show SFME as a promising technique since energy and processing time are dramatically reduced, while oil quality remains unaffected, when compared to the traditional steam distillation process. This improvement in the performance of the process is based on the elimination of heat and mass transfer resistances which limit the oil extraction rate in steam distillation.

Scale-up of these preliminary experiences to a pilot-plant continuous process requires a deeper knowledge of the process. This knowledge must be translated into a mathematical model which represents the influence of process variables on the performance of the extraction process.

In this paper a phenomenological model of the process is developed and checked against batch experimental data. This model is developed from a previous one [3] obtained to describe essential oil steam distillation of lavandin super (Lavandula latifolia x angustifolia). Modifications are based on theoretical knowledge and experimental evidence.

References

[1] Lucchesi ME, Chemat F, Smadja J, "An original solvent free microwave extraction of essential oils from spices", Flavour and Fragrance Journal 19 (2) pp. 134-138 (2004)

[2] Lucchesi, ME, Chemat, F, Smadja, J, "Solvent-free microwave extraction of essential oil from aromatic herbs: comparison with conventional hydro-distillation", J Chromatogr. A 1043(2), 323-327 (2004)

[3] Cerpa MG, Mato RB, Cocero MJ, "Modeling steam distillation of essential oils: Application to lavandin super oil", AIChE J., 54(4), 909-917 (2008)